1. Field of the Invention
This disclosure relates to the field of integrity testing for endoscopes, in particular to computer systems and software to carry out such integrity testing.
2. Description of the Related Art
As medical science has advanced, it has recognized that the ability of diagnostic evaluation procedures to detect various maladies early in their development provides one of the primary tools in preventing adverse outcomes. At the same time, highly invasive procedures, even if effective at their intended task, introduce their own dangers. Invasive procedures require a long time to heal, are expensive, and can result in additional costs due to extensive hospitalization, additional therapies to recuperate, and lost productive time. In an attempt to provide for medical services at reasonable cost to most of the population, it is desirable to have maladies detected, and treated early and to provide both the detection and intervention using procedures which are as minimally invasive as possible to speed up recovery time and reduce risks introduced from the performance of the procedure.
To provide for many minimally invasive procedures, medicine has seen a dramatic rise in the use of endoscopic instruments. Traditionally, extensive invasion of the body was required to allow a surgeon to see where he was working as well as to allow the body to admit his hands, which are relatively large instruments, during a procedure. The use of endoscopes provides for an alternative solution in both cases. Endoscopes are long slender medical instruments which can be inserted through a relatively small orifice in the body. With advanced optics, an endoscope can allow a doctor to see structures without the need for invasive surgery and often better than his normal eyesight would permit. Further, by including specially designed and small-sized instruments, a doctor's hands need not be admitted into the body of the patient to perform procedures which allows for still further reductions in the need for large entry points. Endoscopic surgical tools have advanced greatly in recent years allowing a doctor to examine internal structures, take biopsies, and even perform some types of surgery. While many endoscopic procedures utilize one or more small incisions, others utilize natural body openings such as the mouth, nose, ear, rectum, vagina, or urethra. The latter type of endoscopes are particularly useful when related to disease of the gastrointestinal tract or reproductive system and because they are inserted in naturally occurring openings, are considered to be minimally invasive.
An endoscope is generally used in a procedure by being inserted into the opening (whether natural or artificial) by a doctor trained in its use. The endoscope is then guided to the area to be examined through the use of an external control on the end of the endoscope remaining outside the body. In some cases, such as when the colon is being examined, the path taken by the endoscope is itself evaluated. In some alternative cases, the endoscope is maneuvered to reach a particular destination which is to be examined or operated on. In either case, to facilitate the movement of the endoscope, the endoscope is generally a long flexible tube sized and shaped for the particular procedure to be performed and will be capable of being guided through body structures, without damage, through what is often a convoluted path.
The endoscope will include instruments related to its function and the particular procedure being performed. These instruments will generally first provide for visual or other detection apparatus and related image recordation. These instruments will serve first to allow the operator to guide the instrument, but also to provide records of what was done and to store particular images for later evaluation. The tube may also include ports on the portion external to the body which allow for medications, water, air, or instruments to be inserted externally and passed through the endoscope to the point where the internal end of the endoscope is located. The instruments can then extend from the internal end of the endoscope to allow for the performance of medical activities. These instruments will generally be controlled externally while what they are doing is monitored using the detection apparatuses. Endoscope procedures may include, but are not limited to, biopsies of material; the introduction of medical agents, irrigation water, or apparatuses; cleaning of an area for improved visual characteristics; and some surgical procedures.
In most endoscopes, either the natural orifice through which it is inserted defines a maximum size of the scope, or the scope is generally desired to be as small as possible to minimize the size of an incision necessary to insert it. At the same time, it is necessary for the endoscopes to include control mechanisms outside the body, as well as generally sophisticated cameras or other imaging apparatus, and ports for, or inclusion of, medical application delivery devices. Further, electronics and systems to allow for signals to be transported from the control device outside the body to the tip of the endoscope which is inaccessible inside the body are necessary. Hook-ups to external computers to provide for interpretation of data signals are also generally required. All of these sophisticated systems make endoscopes quite expensive and sophisticated devices. Further, the popularity of endoscopic procedures means that most medical providers need a relatively large number of endoscopes, even of similar type, in order to be able to provide for all the procedures they are used for.
Even while use of endoscopic instruments is minimally invasive, without proper care, they can still transmit disease. It is necessary that endoscopes be well cleaned and sterilized after each use to prevent transfer of potentially dangerous agents between patients. Endoscopes will also often operate in what can be considered a wet environment or other environment where body fluids are in contact with the exterior of the endoscope which is generally a form of rubber tubing. Cleaning and sterilization systems also often utilize liquids in cleaning. Because an endoscope's sophisticated design uses a high number of components which can be adversely effected by moisture, generally an endoscope will be sealed from external fluid invasion by having its components sealed inside the flexible plastic or rubber sleeve. Components which are not sealed during use are alternatively sealed by caps during cleaning as the entire instrument can be inserted in liquid during the cleaning process.
The plastic or rubber sleeve can fail over time and develop holes or fractures from repeated use and general wear and tear. Further, improper handling or use of the scope can damage the sleeve. If the sleeve develops holes, cracks or other points of failure, it can allow the introduction of moisture to the internal components of the endoscope. If this occurs inside the body of a patient, it may allow microorganisms to travel with the endoscope. More commonly, however, the failure will allow for cleaning agents to get inside the endoscope. Any of these intrusions to the endoscope can be dangerous to the endoscope. Even a single drop of water inside the endoscope can result in sensitive electronic devices becoming damaged and the endoscope becoming unusable. Further, the intrusion of even a small amount of body fluid can result in a non-sterile instrument.
Beyond the possibility of fluid intrusion from cracks or breaks in the coating, most endoscopes are required to have some access to internal structures to allow for external devices, such as computers, to operate in connection to the internal components. In use, these ports are generally plugged by a connector or similar device. After use, a sealer cap or related device is generally placed in the ports to seal them from external invasion. These caps can also develop holes, seals can break down, or protective covers may be incorrectly installed. Any of these situations can also lead to fluid invasion of the endoscope.
To clean endoscopes between procedures, generally the endoscope is first disconnected from associated computer apparatus, is wiped down and open channels are suctioned and washed to remove most of the material on the scope. The scope is then sent to be cleaned. As cleaning requires specific immersion or saturation of the endoscope with liquid materials, it is important that the scope be checked for leaks prior to this cleaning; otherwise a leak could admit cleaning materials and damage the endoscope. Traditionally, leaks were tested for by a technician who would access the internal structure of the endoscope, and if a leak was detected, connect an air source and introduce air to raise the internal pressure of the scope above the ambient to inhibit fluid invasion during cleaning and prior to repair.
In the most basic test methodology, the scope was immersed in fluid (usually water) while held at a positive pressure and left there for a period of time. During this time, the technician would look for bubbles rising from the endoscope indicating loss of air from the internal structure. This methodology was fraught with problems. In the first instance, placing the structure in water tended to produce bubbles. Further, solutions used to initially clean the endoscope could themselves create bubbles when interacting with the water. Still finally, movement of the scope in the water could conceal or introduce bubbles.
To try and get around this problem, systems were introduced which allowed the internal area of the endoscope to be pumped to a particular pressure. The user would then watch a gauge or indicator to determine if the pressure decreased over a period of time. Other systems tried to automate the provision of air, and the monitoring of pressure. One such system is described in U.S. Pat. No. 6,408,682, the entire disclosure of which is herein incorporated by reference.
Integrity testers for endoscopes which rely on purely human control to determine if a leak exists are fraught with problems. The human user would pump up the internal area of the endoscope to about the desired pressure, but pumps could be unreliable and gauges may not actually indicate true pressure. The user then reviewed what was usually an analog gauge for any movement of the needle downward indicative of a leak. While fairly large leaks were readily noticeable, smaller leaks may not be noticed as the ability to notice them would be dependent both on the user's ability to read a gauge, which could have a large amount of wiggle, and the willingness of the user to watch the gauge long enough to make sure that any loss is detected.
Automated systems generally were not much better. While these systems allowed for machine monitoring of the internal pressure which allowed for more accurate calculation, the systems generally relied on volume changes which are inaccurate due to the rubbery nature of the sleeve material. Further, the systems did not provide for processor control related to humidity testing in addition to pressure testing.